Objective:
1) Conserve, regenerate, back-up, and distribute genetic resources and associated information for wheat, barley, oats, rye, rice, and other small grains and related wild species. More than 140,000 small grains accessions will be conserved. Each year 5-10 percent of National Small Grains Collection (NSGC) accessions will be regenerated. Seeds and associated information will be distributed on request to scientists. 2) Conduct genetic characterizations and phenotypic evaluations of wheat, barley, oats, rye, and other small grains and related wild species for priority genetic and agronomic traits. Apply the preceding knowledge to genetic resource acquisition and curation of selected taxa. Ploidy levels of wheat landraces and wild species of wheat, barley, and oats will be verified. Characterization data will be completed for key descriptors in wheat, barley, and oats. Kernel hardness will be determined for accessions of common bread wheat. 3) Identify and genetically characterize host-plant resistance to the virulent stem rust race Ug99 from NSGC wheat accessions.

Approach:
Established procedures will be followed to maintain all NSGC germplasm accessions, with special attention to seed preparation and planting, plant pathogen monitoring, harvest, and laboratory processing. Seed of NSGC accessions are held in medium-term storage under controlled temperature (5-6 C) and relative humidity (25%). Inventory records, including quantity of seed on hand, viability, and date of last regeneration, are maintained in GRIN. Accessions will be scheduled for regeneration based on a priority matrix. Seed will be provided to the NCGRP for safety back up. Standard procedures for GRIN Order Processing will be followed. Distributions outside of the US will follow phytosanitary requirements of the recipient country, including import permits, phytosanitary certificates, and additional declarations. USDA-APHIS will be consulted regularly for the latest information on seed export. The ploidy analyses will be conducted with the Partec CyFlow Ploidy Analyser® following protocols from the manufacturer and modifications developed locally for more efficient analyses of small grains species. Descriptor data will primarily be collected from the voucher images, but direct field and laboratory observations will also be used. Kernel hardness analyses will be performed with the Perten® Single Kernel Characterization System (SKCS 4100), which is the wheat industry standard and is supported by USDA-Federal Grain Inspection Service. To identify new sources of resistance to the Ug99 lineage of Pgt, winter habit wheat landraces from the NSGC will be screened. Because field testing capacity at Njoro, Kenya is limited, the accessions will first be tested for adult plant resistance to US races in field trials St. Paul, MN in cooperation with an ARS scientist at the USDA-ARS Cereal Disease Laboratory (CDL). Accessions with resistance to the US races will then be tested as adult plants in the field for resistance to Ug99 and its variants in the USDA nursery in Kenya. Accessions showing resistance in one Kenya test will be re-tested to confirm results and tested for seedling resistance to race TTKSK at the CDL. To map resistance to the Ug99 lineage of Pgt in spring wheat landraces and ascertain the relationship to known sources of resistance, mapping populations will be developed from crosses previously made with the susceptible spring line LMPG-6. Mapping populations will be generated either through single seed descent to the F6 generation or through doubled haploid (DH) production. At least 150 DH lines or recombinant inbred lines (RIL) per cross will be generated. The lines will be evaluated for adult plant resistance in the USDA nursery in Kenya and as seedlings against race TTKSK at the CDL.